Polyester resin composition, molded article, and production method therefor

Abstract

To provide a resin composition and a molded article which are less apt to generate isocyanate gas and which contain few foreign particles and hence have better surface appearance.SOLUTION: A resin composition comprising a polyester resin (A) and one or more carbodiimide compounds, wherein the carbodiimide compounds include a carbodiimide compound (B) represented by general formula (1), and when the surface of a molded article comprising the resin composition is examined with an optical microscope, the number of observed foreign particles each having an area of 100 μm2 or larger is less than 10 per 100 cm2.

Description

[Technical Field]

[0001] The present disclosure relates to a polyester resin composition, a molded article, and a method for producing the same. [Background technology]

[0002] Polyester resins such as polybutylene terephthalate (PBT) are prone to hydrolysis due to the ester groups in their molecular structure, and additives have been investigated to improve their hydrolysis resistance. In particular, it is known that adding carbodiimide compounds to PBT can improve hydrolysis resistance, but this has the problem of generating toxic isocyanates when heated. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2013 / 146625 [Patent Document 2] Japanese Patent Application Publication No. 2020-176167 Summary of the Invention [Problem to be solved by the invention]

[0004] Use of a cyclic carbodiimide as the carbodiimide compound can suppress the generation of isocyanate gas (for example, Patent Document 1). Furthermore, use of a carbodiimide compound having a predetermined structure can reduce the generation of isocyanate gas (for example, Patent Document 2). However, it has been found that even when the generation of isocyanate gas during heating is small, the surface appearance of the resulting molded article may deteriorate. An object of the present disclosure is to provide a resin composition and a molded article that generate less isocyanate gas and have a better surface appearance. [Means for solving the problem]

[0005] The present disclosure has the following aspects. [1] A polyester resin (A), a carbodiimide compound; and a resin composition comprising the The carbodiimide compound contains a carbodiimide compound (B) represented by the following general formula (1), and when the surface of a molded article containing the resin composition is observed with an optical microscope, the surface has a thickness of 100 μm 2 The number of foreign objects with an area of 10 or more per 100cm 2 The resin composition, TIFF2025118130000001.tif18170(In general formula (1), R 1 , R 3 represents a residue of an organic compound having one functional group capable of reacting with an isocyanate group, excluding the functional group; R 1 , R 3 may be the same or different. 2 represents a divalent residue obtained by removing two isocyanate groups from a diisocyanate compound. 2 has a benzene-based aromatic ring directly bonded to the NCN group, and has no or only one substituent at both ortho positions of the benzene-based aromatic ring bonded to the NCN group. 1 , X 2 represents a group formed by a reaction between the functional group of the organic compound and the isocyanate group of the diisocyanate compound, and X 1 , X 2 may be the same or different. n represents a number from 1 to 15. The diisocyanate compound contains a mixture of 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, and when the total amount of the diisocyanate compound is taken as 100 mol %, the proportion of the 2,4'-diphenylmethane diisocyanate is 30 to 70 mol %, and the proportion of the 4,4'-diphenylmethane diisocyanate is 30 to 70 mol %. [2] The resin composition according to [1], wherein the amount of isocyanate gas generated when the resin composition is heated at 260°C for 10 minutes is less than 100 ppm. [3] The resin composition according to [1] or [2], comprising 0.1 to 5 parts by mass of the carbodiimide compound (B) per 100 parts by mass of the polyester resin (A). [4] The resin composition according to any one of [1] to [3], wherein the polyester resin (A) contains polybutylene terephthalate. [5] The resin composition according to any one of [1] to [4], which contains a resin (C) different from the polyester resin (A). [6] A molded article comprising the resin composition according to any one of [1] to [5], 100 μm observed on the surface of the molded product through an optical microscope 2 The number of foreign objects with an area of 10 or more per 100cm 2 less than, [7] The molded article according to [6], wherein the amount of isocyanate gas generated when the molded article is heated at 260°C for 10 minutes is less than 100 ppm. [8] The molded article according to [6] or [7], wherein the carbodiimide compound (B) is contained in an amount of 0.1 to 5 parts by mass per 100 parts by mass of the polyester resin (A). [9] A method for producing a resin composition containing a polyester resin (A) and a carbodiimide compound (B) represented by the following general formula (1), comprising the following step (I) or step (II): Step (I): A step including: a first step of kneading the carbodiimide compound (B) with a resin (C) different from the polyester resin (A) to obtain a masterbatch; and a second step of kneading the polyester resin (A) with the masterbatch; Step (II): A step comprising kneading the polyester resin (A) and the carbodiimide compound (B) in an extruder, wherein the temperature of the extruder inlet port when the carbodiimide compound (B) is introduced into the extruder is 200°C or lower; A method for producing a resin composition. TIFF2025118130000002.tif17170(In general formula (1), R 1 , R 3 represents a residue of an organic compound having one functional group capable of reacting with an isocyanate group, excluding the functional group; R1 , R 3 may be the same or different. 2 represents a divalent residue obtained by removing two isocyanate groups from a diisocyanate compound. 2 has a benzene-based aromatic ring directly bonded to the NCN group, and has no or only one substituent at both ortho positions of the benzene-based aromatic ring bonded to the NCN group. 1 , X 2 represents a group formed by a reaction between the functional group of the organic compound and the isocyanate group of the diisocyanate compound, and X 1 , X 2 may be the same or different. n represents a number from 1 to 15. The diisocyanate compound contains a mixture of 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, and when the total amount of the diisocyanate compound is taken as 100 mol %, the proportion of the 2,4'-diphenylmethane diisocyanate is 30 to 70 mol %, and the proportion of the 4,4'-diphenylmethane diisocyanate is 30 to 70 mol %.

[10] The method for producing a resin composition according to [9], wherein the first step in the step (I) is carried out using an extruder, and the temperature of the extruder inlet section when the carbodiimide compound (B) is introduced into the extruder is 200°C or lower.

[11] The method for producing a resin composition according to [9], wherein in step (II), the carbodiimide compound (B) is introduced into the extruder in the form of a masterbatch containing the carbodiimide compound (B) and a resin (C) different from the polyester resin (A).

[12] The method for producing a resin composition according to any one of [9] to

[11] , wherein the masterbatch contains 10 to 90 parts by mass of carbodiimide per 100 parts by mass of the masterbatch. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to provide a resin composition and a molded article that generate less isocyanate gas and have a better surface appearance. DETAILED DESCRIPTION OF THE INVENTION

[0007] An embodiment of the present invention will be described in detail below. The present invention is not limited to the following embodiment, and can be implemented by making appropriate changes within the scope that does not impair the effects of the present invention. The configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible as appropriate within the scope of the gist of the present embodiment. The present embodiment is not limited to the embodiments, but is limited only by the claims. Each feature disclosed herein may be combined with any other feature disclosed herein. When a specific description given for one embodiment also applies to other embodiments, that description may be omitted in the other embodiments. In this embodiment, the expression "X to Y" regarding a numerical range means "not less than X and not more than Y."

[0008] [First embodiment: resin composition] The first embodiment of the present disclosure is A resin composition comprising a polyester resin (A) and a carbodiimide compound, The carbodiimide compound contains a carbodiimide compound (B) represented by the following general formula (1), and when the surface of a molded article containing the resin composition is observed with an optical microscope, the surface of the molded article has a thickness of 100 μm. 2 The number of foreign objects with an area of 10 or more per 100cm 2 The present invention relates to a resin composition having a viscosity of less than 1000 MPa. TIFF2025118130000003.tif17170(In general formula (1), R 1 , R 3 represents a residue of an organic compound having one functional group capable of reacting with an isocyanate group, excluding the functional group; R 1 , R 3 may be the same or different. 2represents a divalent residue obtained by removing two isocyanate groups from a diisocyanate compound. 2 has a benzene-based aromatic ring directly bonded to the NCN group, and has no or only one substituent at both ortho positions of the benzene-based aromatic ring bonded to the NCN group. 1 , X 2 represents a group formed by a reaction between the functional group of the organic compound and the isocyanate group of the diisocyanate compound, and X 1 , X 2 may be the same or different. n represents a number from 1 to 15. The diisocyanate compound contains a mixture of 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, and when the total amount of the diisocyanate compound is taken as 100 mol %, the proportion of the 2,4'-diphenylmethane diisocyanate is 30 to 70 mol %, and the proportion of the 4,4'-diphenylmethane diisocyanate is 30 to 70 mol %. According to the first embodiment, it is possible to provide a resin composition and a molded article that generate less isocyanate gas and have less foreign matter, and therefore have a better surface appearance.

[0009] <Polyester resin (A)> In one embodiment, the polyester resin (A) may be a C polyester resin such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT), or polybutylene terephthalate (PBT). 2-6 Examples of the polyester resin (A) include alkylene arylate resins. One or more resins selected from the above can be used.

[0010] In one embodiment, the polyester resin (A) preferably comprises polybutylene terephthalate. In one embodiment, the polyester resin (A) contains at least terephthalic acid or an ester-forming derivative thereof (C 1-6It is preferable that the polybutylene terephthalate is obtained by polycondensation of a dicarboxylic acid component containing an alkylene glycol having at least 4 carbon atoms (1,4-butanediol) or an ester-forming derivative thereof (acetylated product, etc.) and a glycol component containing an alkylene glycol having at least 4 carbon atoms (1,4-butanediol) or an ester-forming derivative thereof (acetylated product, etc.). In one embodiment, the polybutylene terephthalate contained in the polyester resin (A) is not limited to homopolybutylene terephthalate, and may be a copolymer containing 60 mol % or more of butylene terephthalate units.

[0011] The amount of terminal carboxyl groups in the polybutylene terephthalate contained in the polyester resin (A) is not particularly limited as long as it does not impede the object of the present disclosure, but is preferably 30 meq / kg or less, more preferably 25 meq / kg or less.

[0012] The intrinsic viscosity of the polybutylene terephthalate resin is not particularly limited as long as it does not impair the objectives of the present disclosure, but is preferably 0.60 dL / g to 1.2 dL / g, and more preferably 0.65 dL / g to 0.9 dL / g. When a polybutylene terephthalate resin having an intrinsic viscosity within this range is used, the resulting polybutylene terephthalate resin composition exhibits particularly excellent moldability. The intrinsic viscosity can also be adjusted by blending polybutylene terephthalate resins having different intrinsic viscosities. For example, a polybutylene terephthalate resin having an intrinsic viscosity of 0.9 dL / g can be prepared by blending a polybutylene terephthalate resin having an intrinsic viscosity of 1.0 dL / g with a polybutylene terephthalate resin having an intrinsic viscosity of 0.7 dL / g. The intrinsic viscosity of the polybutylene terephthalate resin can be measured, for example, in o-chlorophenol at 35°C.

[0013] In preparing polybutylene terephthalate resin, when an aromatic dicarboxylic acid other than terephthalic acid or an ester-forming derivative thereof is used as a comonomer component, for example, C 3 esters such as isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4'-dicarboxydiphenyl ether are used.8-14 Aromatic dicarboxylic acids; succinic acid, adipic acid, azelaic acid, sebacic acid, etc. 4-16 Alkanedicarboxylic acids such as cyclohexanedicarboxylic acid 5-10 cycloalkanedicarboxylic acids; ester-forming derivatives of these dicarboxylic acid components (C 1-6 These dicarboxylic acid components can be used alone or in combination of two or more kinds. Among these dicarboxylic acid components, C 8-12 Aromatic dicarboxylic acids such as adipic acid, azelaic acid, and sebacic acid 6-12 The alkanedicarboxylic acids are more preferred.

[0014] In the preparation of polybutylene terephthalate, when a glycol component other than 1,4-butanediol is used as a comonomer component, for example, C 1,4-butanediol such as ethylene glycol, propylene glycol, trimethylene glycol, 1,3-butylene glycol, hexamethylene glycol, neopentyl glycol, 1,3-octanediol, etc. 2-10 alkylene glycols; polyoxyalkylene glycols such as diethylene glycol, triethylene glycol, and dipropylene glycol; alicyclic diols such as cyclohexanedimethanol and hydrogenated bisphenol A; aromatic diols such as bisphenol A and 4,4'-dihydroxybiphenyl; C-type bisphenol A compounds such as ethylene oxide 2-mol adduct of bisphenol A and propylene oxide 3-mol adduct of bisphenol A 2-4 or ester-forming derivatives of these glycols (acetylated products, etc.). These glycol components can be used alone or in combination of two or more. Among these glycol components, C such as ethylene glycol and trimethylene glycol 2-6 More preferred are alkylene glycols such as those listed above, polyoxyalkylene glycols such as diethylene glycol, and alicyclic diols such as cyclohexanedimethanol.

[0015] Examples of comonomer components that can be used in addition to the dicarboxylic acid component and the glycol component include aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and 4-carboxy-4'-hydroxybiphenyl; aliphatic hydroxycarboxylic acids such as glycolic acid and hydroxycaproic acid; C hydroxycarboxylic acids such as propiolactone, butyrolactone, valerolactone, and caprolactone (ε-caprolactone, etc.); 3-12 Lactones; ester-forming derivatives of these comonomer components (C 1-6 alkyl ester derivatives, acid halides, acetylated derivatives, etc.

[0016] The content of the polyester resin (A) is preferably 30 to 100 mass% of the total mass of the resin composition, more preferably 30 to 90 mass%, even more preferably 50 to 80 mass%, and particularly preferably 60 to 70 mass%. The content of the polyester resin (A) in the thermoplastic resin contained in the resin composition is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and may be 100% by mass.

[0017] <Carbodiimide compound (B)> The carbodiimide compound (B) used in the resin composition according to the first embodiment is a compound having a carbodiimide group (—N═C═N—) in the molecule and is represented by the following general formula (1). TIFF2025118130000004.tif18170(In general formula (1), R 1 , R 3 represents a residue of an organic compound having one functional group capable of reacting with an isocyanate group, excluding the functional group; R 1 , R 3 may be the same or different. 2 represents a divalent residue obtained by removing two isocyanate groups from a diisocyanate compound. 2has a benzene-based aromatic ring directly bonded to the NCN group, and has no or only one substituent at both ortho positions of the benzene-based aromatic ring bonded to the NCN group. 1 , X 2 represents a group formed by a reaction between the functional group of the organic compound and the isocyanate group of the diisocyanate compound, and X 1 , X 2 may be the same or different. n represents a number from 1 to 15. The diisocyanate compound contains a mixture of 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, and when the total amount of the diisocyanate compound is taken as 100 mol %, the proportion of the 2,4'-diphenylmethane diisocyanate is 30 to 70 mol %, and the proportion of the 4,4'-diphenylmethane diisocyanate is 30 to 70 mol %.

[0018] In one embodiment, the diisocyanate compound is preferably a mixture of 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate. When the total amount of the diisocyanate compound is taken as 100 mol%, the proportion of 2,4'-MDI is preferably 30 to 70 mol% and the proportion of 4,4'-MDI is preferably 30 to 70 mol%. When the proportion of 2,4'-MDI is 30 mol% or more, the carbodiimide compound (B) is less likely to gel, and storage stability and solubility in solvents can be improved. Furthermore, by keeping the proportion of 2,4'-MDI at 70 mol% or less, steric hindrance is not too great, the reactivity of the carbodiimide compound (B) is improved, and desired performance can be easily achieved when used with the polyester resin (A). From this viewpoint, the proportion of 2,4'-MDI in the above diisocyanate compound is more preferably 40 to 65 mol %, and even more preferably 50 to 60 mol %, and the proportion of 4,4'-MDI is more preferably 35 to 60 mol %, and even more preferably 40 to 50 mol %.

[0019] In general formula (1), R 1 , R 3represents a residue of an organic compound having one functional group capable of reacting with an isocyanate group, excluding the functional group; R 1 , R 3 The organic compound having one functional group capable of reacting with an isocyanate group (hereinafter also simply referred to as "organic compound") is not particularly limited as long as it has one functional group capable of reacting with an isocyanate group, but from the viewpoint of reactivity, it is preferably one or more compounds selected from monoisocyanates, monoalcohols, monoamines, monocarboxylic acids, and acid anhydrides.

[0020] (n) In the above general formula (1), n represents a number of 1 to 15. From the viewpoint of suppressing an increase in the melt viscosity of the polyester resin composition, n is preferably 1 to 9.

[0021] Monoisocyanates are preferred because they can increase the content of carbodiimide groups in the carbodiimide compound (B). Examples of monoisocyanates include lower alkyl isocyanates such as methyl isocyanate, ethyl isocyanate, propyl isocyanate, n-, sec-, or tert-butyl isocyanate; alicyclic isocyanates such as cyclohexyl isocyanate; and aromatic isocyanates such as phenyl isocyanate, tolyl isocyanate, dimethylphenyl isocyanate, and 2,6-diisopropylphenyl isocyanate. Among these, from the viewpoint of reactivity, phenyl isocyanate and tolyl isocyanate are preferred, and phenyl isocyanate is more preferred.

[0022] Monoalcohols are preferred because they have high reactivity with isocyanate groups and make it easier to synthesize the carbodiimide compound (B). Examples of monoalcohols include aliphatic alcohols, alicyclic alcohols, polyether monools, etc. Examples of such monoalcohols include methanol, ethanol, 1-propanol, isopropanol, 1-butanol, 2-butanol, 2-methylpropanol, 2-methyl-2-propanol, 2-ethylhexanol, cyclohexanol, dodecyl alcohol, polyethylene glycol monomethyl ether, and polypropylene glycol monomethyl ether. Among these, from the viewpoint of providing an excellent handleability of the resulting carbodiimide compound (B) and good processability with the polyester resin (A), methanol, ethanol, 1-propanol, isopropanol, 1-butanol, 2-butanol, 2-methylpropanol, 2-methyl-2-propanol, 2-ethylhexanol, cyclohexanol, and dodecyl alcohol are preferred, and 1-propanol, isopropanol, 1-butanol, 2-butanol, 2-methylpropanol, 2-methyl-2-propanol, 2-ethylhexanol, and dodecyl alcohol are more preferred.

[0023] Monoamines are preferred because they have high reactivity with isocyanate groups, making it easy to synthesize the carbodiimide compound (B), and because they have excellent compatibility with the polyester resin (A). Examples of monoamines include primary or secondary alkylamines. Examples of such monoamines include primary amines such as butylamine and cyclohexylamine; and secondary amines such as diethylamine, dibutylamine, and dicyclohexylamine. Among these, butylamine and cyclohexylamine are preferred, and butylamine is more preferred, from the viewpoint of improving processability with the polyester resin (A).

[0024] The monocarboxylic acid and the acid anhydride react with the isocyanate group to form a bond site (X in the above general formula (1)). 1 , X 2 ) is preferred in terms of its excellent heat resistance. Examples of monocarboxylic acids include formic acid, acetic acid, propionic acid, isovaleric acid, hexanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, etc. Among these, from the viewpoint of improving processability with the polyester resin (A), acetic acid and propionic acid are preferred, and acetic acid is more preferred. Examples of the acid anhydride include phthalic anhydride, acetic anhydride, succinic anhydride, maleic anhydride, benzoic anhydride, etc. From the viewpoint of improving processability with the polyester resin (A), acetic anhydride and succinic anhydride are preferred, and acetic anhydride is more preferred.

[0025] (X 1 , X 2 ) In the above general formula (1), X 1 , X 2 represents a group formed by the reaction of a functional group capable of reacting with an isocyanate group of the organic compound with the isocyanate group of the diisocyanate compound, and X 1 , X 2 For example, when the organic compound is a monoisocyanate, X 1 , X 2 is a group represented by the following formula (I), and when the organic compound is a monoalcohol, X 1 , X 2 is a group represented by the following formula (II), and when the organic compound is a monoamine, X 1 , X 2 is a group represented by the following formula (III), and when the organic compound is a monocarboxylic acid, X 1 , X 2 is a group represented by the following formula (IV), and when the organic compound is an acid anhydride, X 1 , X 2 is a group represented by the following formula (V).

[0026] TIFF2025118130000005.tif11170

[0027] TIFF2025118130000006.tif23170

[0028] TIFF2025118130000007.tif38170

[0029] TIFF2025118130000008.tif22170

[0030] TIFF2025118130000009.tif36170By including the carbodiimide compound (B) represented by the above general formula (1), a resin composition that generates less isocyanate gas can be obtained.Although the carbodiimide compound can be used in combination with other carbodiimide compounds other than the carbodiimide compound (B), from the viewpoint of further suppressing the generation of isocyanate gas, it is preferable to configure the resin composition so that it consists of the carbodiimide compound (B).

[0031] In one embodiment, it is preferable that the amount of isocyanate gas generated when the resin composition is heated at 260° C. for 10 minutes is less than 100 ppm. When the resin composition is heated at 260° C. for 10 minutes, the amount of isocyanate gas generated is less than 100 ppm, and the resin composition and molded article are therefore more excellent in safety.

[0032] In one embodiment, the content of the carbodiimide compound (B) in the resin composition is preferably 0.1 to 5 parts by mass, more preferably 0.1 to 4 parts by mass, even more preferably 0.2 to 3 parts by mass, and particularly preferably 0.3 to 2 parts by mass, relative to 100 parts by mass of the polyester resin (A). By setting the content of the carbodiimide compound (B) within the above range relative to 100 parts by mass of the polyester resin (A), it is possible to provide a resin composition and a molded article with better surface appearance due to less generation of isocyanate gas and less foreign matter.

[0033] In one embodiment, it is preferable to contain a resin (C) different from the polyester resin (A). By containing a resin (C) different from the polyester resin (A), it is possible to provide a resin composition and a molded article having a better surface appearance due to less isocyanate gas generation during heating and less foreign matter. In one embodiment, examples of the resin (C) different from the polyester resin (A) include polyethylene resin, polypropylene resin, polybutylene succinate resin, polybutylene terephthalate resin, polyamide resin, polycarbonate resin, polyarylene sulfide resin, polyacetal resin, acrylonitrile-styrene resin, acrylonitrile-butadiene-styrene resin, polysulfone resin, polyethersulfone resin, polyetherimide resin, polyetherketone resin, etc. The resin (C) can be one or more selected from the above. The content of the resin (C) is preferably 0.1 to 5 parts by mass, and more preferably 0.1 to 3 parts by mass, relative to 100 parts by mass of the polyester resin (A).

[0034] <100 μm observed when observing the surface of a molded product containing a resin composition with an optical microscope 2 Number of foreign objects with an area of more than In this embodiment, the surface of a molded article containing a resin composition is observed under an optical microscope. 2 The number of foreign objects with an area of 10 or more per 100cm 2 The surface of a molded article containing a resin composition is observed under an optical microscope to have a particle size of less than 100 μm. 2 The number of foreign objects with an area of 10 or more per 100cm 2 By making the temperature less than 100°C, it is possible to provide a resin composition and a molded article having a better surface appearance, with a resin composition that generates less isocyanate gas, and to prevent a decrease in strength due to foreign matter. In this specification, the "number of foreign matters" is calculated by calculating the area of the target surface of a molded product of any shape, and observing it with an optical microscope set at any magnification, and counting the number of foreign matters within 100 μm 2Count the foreign objects with an area of 100cm or more. 2 The number of foreign objects per 100cm is calculated by converting the number of foreign objects per 100cm. 2 The "foreign matter" is observed under an optical microscope as a discolored area.

[0035] In one embodiment, the surface of a molded article containing the resin composition is observed with an optical microscope. 2 The number of foreign objects with an area of 9 or more per 100cm 2 Preferably less than 8 pieces / 100cm 2 It is more preferable that the number is less than 7 pieces / 100cm. 2 Even more preferably, it is less than 6 pieces / 100cm 2 It is more preferable that the number of pieces is less than 5 pieces / 100cm. 2 It is particularly preferred that it is less than 10 ... Number of foreign objects: 10 / 100cm 2 As a method for making the viscosity less than 1000 ppm, for example, a method including the following step (I) or step (II) during production of the resin composition can be mentioned. Step (I): A step including: a first step of kneading the carbodiimide compound (B) with a resin (C) different from the polyester resin (A) to obtain a masterbatch; and a second step of kneading the polyester resin (A) with the masterbatch; Step (II): A step comprising kneading the polyester resin (A) and the carbodiimide compound (B) in an extruder, wherein the temperature of the extruder inlet section when the carbodiimide compound (B) is introduced into the extruder is 200°C or lower. The details of steps (I) and (II) will be described later.

[0036] (Other ingredients) The resin composition of the embodiment of the present disclosure can be blended with known substances that are generally added to thermoplastic resins and thermosetting resins, for example, stabilizers such as antioxidants and ultraviolet absorbers, reinforcing fillers such as circular cross-section glass fibers, antistatic agents, colorants such as dyes and pigments, mold release agents, lubricants, crystallization accelerators, crystal nucleating agents, etc., to impart desired properties according to the purpose, within a range that does not impair the effects of the present disclosure.

[0037] (Method of producing resin composition) The method for producing the resin composition according to the present embodiment is not particularly limited, and the resin composition can be prepared by a conventionally known method. For example, the resin composition is prepared by blending the components and melt-kneading them using a single-screw or twin-screw extruder. In one embodiment, the resin composition according to this embodiment is preferably produced by a method for producing a resin composition according to an embodiment described below.

[0038] [Second embodiment: molded product] The second embodiment of this embodiment is as follows: A molded article comprising the resin composition, 100 μm observed on the surface of the molded product through an optical microscope 2 The number of foreign objects with an area of 10 or more per 100cm 2 The present invention relates to articles having a thickness of less than 1 / 2 mm. According to the second embodiment, it is possible to provide a resin composition and a molded article that generate less isocyanate gas and have less foreign matter, resulting in a better surface appearance.

[0039] The molded article of this embodiment is a molded article containing the resin composition of the above embodiment. The molding method is not particularly limited, and known molding methods can be used. For example, the molded article can be produced by (1) mixing the components, kneading and extruding them in a single- or twin-screw extruder to prepare pellets, and then molding them; (2) first preparing pellets (master batches) with different compositions, mixing (diluting) a predetermined amount of the pellets, and molding them to obtain a molded article of the desired composition; or (3) directly charging one or more of the components into a molding machine. The pellets may be prepared, for example, by melt-mixing components other than a brittle component (such as a glass-based reinforcing material) and then mixing the brittle component. The molding method for other molded articles made of thermoplastic resins is also not particularly limited, and known molding methods can be used.

[0040] The molded article may be produced by melt-kneading the resin composition and molding it by a conventional method such as extrusion molding, injection molding, compression molding, blow molding, vacuum molding, rotational molding, gas injection molding, etc., but is usually molded by injection molding. The mold temperature during injection molding is usually 40 to 120°C, preferably 50 to 90°C, and more preferably about 60 to 80°C.

[0041] The molded article may contain a colorant, such as inorganic pigments (black pigments such as carbon black (e.g., acetylene black, lamp black, thermal black, furnace black, channel black, and ketjen black), red pigments such as iron oxide red, orange pigments such as molybdate orange, and white pigments such as titanium oxide), and organic pigments (yellow pigments, orange pigments, red pigments, blue pigments, and green pigments).

[0042] <100μm observed on the surface of the molded product through an optical microscope 2 Number of foreign objects with an area of more than In this embodiment, the surface of the molded product is observed under an optical microscope. 2 The number of foreign objects with an area of 10 or more per 100cm 2The surface of the molded product is observed under an optical microscope with a particle size of less than 100 μm. 2 The number of foreign objects with an area of 10 or more per 100cm 2 When a resin composition that generates less isocyanate gas is used, a molded article with a better surface appearance can be provided by using a resin composition that generates less isocyanate gas. In this specification, the "number of foreign matters" is calculated by calculating the area of the target surface of a molded product of any shape, and observing it with an optical microscope set at any magnification, and counting the number of foreign matters within 100 μm 2 Count the foreign objects with an area of 100cm or more. 2 The number of foreign objects per 100cm is calculated by converting the number of foreign objects per 100cm. 2 " is a numerical value with units of ".

[0043] In one embodiment, the amount of isocyanate gas generated when the molded article is heated for 10 minutes at 260° C. is preferably less than 100 ppm. Since the amount of isocyanate gas generated when heated for 10 minutes at 260° C. is less than 100 ppm, the molded article of this embodiment is more excellent in safety.

[0044] In one embodiment, the carbodiimide compound is preferably contained in an amount of 0.1 to 5 parts by mass relative to 100 parts by mass of the polyester resin (A). By containing the carbodiimide compound in an amount of 0.1 to 5 parts by mass relative to 100 parts by mass of the polyester resin (A), a molded article that generates less isocyanate gas can be obtained.

[0045] [Third embodiment: Method for producing resin composition] The third embodiment of this embodiment is as follows: A method for producing a resin composition containing a polyester resin (A) and a carbodiimide compound (B) represented by the following general formula (1), the method comprising the following step (I) or step (II): Step (I): A step including: a first step of kneading the carbodiimide compound (B) with a resin (C) different from the polyester resin (A) to obtain a masterbatch; and a second step of kneading the polyester resin (A) with the masterbatch; Step (II): A step comprising kneading the polyester resin (A) and the carbodiimide compound (B) in an extruder, wherein the temperature of the extruder inlet port when the carbodiimide compound (B) is introduced into the extruder is 200°C or lower; The present invention relates to a method for producing a resin composition. TIFF2025118130000010.tif18170(In general formula (1), R 1 , R 3 represents a residue of an organic compound having one functional group capable of reacting with an isocyanate group, excluding the functional group; R 1 , R 3 may be the same or different. 2 represents a divalent residue obtained by removing two isocyanate groups from a diisocyanate compound. 2 has a benzene-based aromatic ring directly bonded to the NCN group, and has no or only one substituent at both ortho positions of the benzene-based aromatic ring bonded to the NCN group. 1 , X 2 represents a group formed by a reaction between the functional group of the organic compound and the isocyanate group of the diisocyanate compound, and X 1 , X 2 may be the same or different. n represents a number from 1 to 15. The diisocyanate compound contains a mixture of 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, and when the total amount of the diisocyanate compound is taken as 100 mol %, the proportion of the 2,4'-diphenylmethane diisocyanate is 30 to 70 mol %, and the proportion of the 4,4'-diphenylmethane diisocyanate is 30 to 70 mol %.

[0046] According to the third embodiment, a resin composition can be produced which generates less isocyanate gas and contains less foreign matter, resulting in a better surface appearance. In one embodiment, the method for producing a resin composition includes step (I). When step (I) is included, the temperature of the extruder inlet when the carbodiimide compound (B) is added to the extruder is not limited and may be, for example, above 200°C. In another embodiment, the method for producing a resin composition includes step (II). When step (II) is included, the carbodiimide compound (B) may be added in the form of a masterbatch or as is.

[0047] In this specification, the term "extruder" refers to a general extruder that is equipped with a raw material charging mechanism (hopper), a cylinder, and at least one screw in the cylinder, and that has a mechanism in which a resin is melted in the cylinder by heat from a temperature control mechanism (heater and cooler) and shear heat from the screw, kneaded while being transported forward by the screw, and extruded from a mold at the end portion called a die. In this specification, the term "extruder charging section" refers to the section of the cylinder directly below the hopper. The temperature of the "extruder charging section" is preferably maintained at a constant temperature by a temperature control mechanism (heater and cooler). The entire cylinder is preferably divided into two or more blocks, and each block is controlled at a different temperature.

[0048] <Process (I)> In this embodiment, step (I) includes a first step of kneading the carbodiimide compound (B) with a resin (C) different from the polyester resin (A) to obtain a masterbatch, and a second step of kneading the polyester resin (A) with the masterbatch. By using a masterbatch containing the carbodiimide compound (B) and a resin (C) different from the polyester resin (A), it is possible to easily produce a resin composition with a better surface appearance due to less generation of isocyanate gas and less foreign matter. (1st step) In the first step, the carbodiimide compound (B) is kneaded with a resin (C) different from the polyester resin (A) to obtain a masterbatch. The different resin (C) is as described above. The method for preparing the masterbatch is not particularly limited, and it can be produced by kneading the carbodiimide compound (B) and a resin (C) different from the polyester resin (A) by a conventional method. For example, the masterbatch can be produced by adding the carbodiimide compound (B) and a resin (C) different from the polyester resin (A) to a mixer to mix them uniformly, and then melting and kneading them in an extruder. The amount of the carbodiimide compound (B) added is preferably 10 to 900 parts by mass, and more preferably 50 to 200 parts by mass, per 100 parts by mass of the resin (C). The blending amount of the resin (C) is preferably 0.1 to 5 parts by mass, and more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the polyester resin (A). In one embodiment, the first step in step (I) is carried out using an extruder, and the temperature of the extruder inlet section when the carbodiimide compound (B) is introduced into the extruder is preferably 200°C or less, more preferably 195°C or less, and even more preferably 190°C or less. The first step in step (I) is carried out using an extruder, and the temperature of the extruder inlet section when the carbodiimide compound (B) is fed into the extruder is 200°C or lower. This prevents a sudden increase in the reaction rate of the dimerization reaction in the cylinder, allows the reaction to proceed gently throughout the extruder, and further suppresses the generation of foreign matter. (2nd process) In the second step, the polyester resin (A) and the masterbatch are kneaded. The kneading temperature is not limited, and is, for example, preferably 230 to 310° C., more preferably 250 to 280° C. The kneading method is not limited, and the kneading can be carried out using a known extruder. The amount of the masterbatch to be blended is preferably an amount such that the amount of the carbodiimide compound (B) blended is 0.1 to 5 parts by mass, and more preferably 0.3 to 2 parts by mass, per 100 parts by mass of the polyester resin (A).

[0049] <Process (II)> In this embodiment, step (II) includes kneading the polyester resin (A) and the carbodiimide compound (B) in an extruder, and is a step in which the temperature of the extruder inlet when the carbodiimide compound (B) is introduced into the extruder is 200°C or lower. By introducing the carbodiimide compound (B) into the extruder at a temperature of 200°C or lower, a resin composition with a better surface appearance can be easily produced with less isocyanate gas and less foreign matter. The temperature of the extruder inlet when the carbodiimide compound (B) is introduced into the extruder is preferably 195°C or lower, and more preferably 190°C or lower. In one embodiment, in step (II), the carbodiimide compound (B) is preferably introduced into the extruder in the form of a masterbatch containing the carbodiimide compound (B) and a resin (C) different from the polyester resin (A). By introducing the carbodiimide compound (B) and a resin (C) different from the polyester resin (A) into the extruder in the form of a masterbatch, less isocyanate gas is generated and less foreign matter is present, making it possible to easily produce a resin composition with a better surface appearance. The method for preparing the masterbatch is not particularly limited, and it can be produced by kneading the carbodiimide compound (B) and a resin (C) different from the polyester resin (A) by a conventional method. For example, the masterbatch can be produced by adding the carbodiimide compound (B) and a resin (C) different from the polyester resin (A) to a mixer to mix them uniformly, and then melting and kneading them in an extruder. The step (II) includes kneading the polyester resin (A) and the carbodiimide compound (B) in an extruder, In step (II), the carbodiimide compound (B) is introduced into the extruder in the form of a masterbatch containing the carbodiimide compound (B) and a resin (C) different from the polyester resin (A). This prevents a rapid dimerization reaction in the cylinder, allows the reaction to proceed gently throughout the extruder, and further suppresses the generation of foreign matter.

[0050] In one embodiment, in the above steps (I) and (II), the masterbatch preferably contains 10 to 90 parts by mass, more preferably 20 to 80 parts by mass, and even more preferably 30 to 70 parts by mass of carbodiimide per 100 parts by mass of the masterbatch. [Example]

[0051] The present embodiment will be described in more detail below by showing examples, but interpretation of the present disclosure is not limited to these examples.

[0052] [Raw materials] The raw materials used in the examples and comparative examples are as follows. <Polyethylene resin> A: Polyplastics polybutylene terephthalate (IV: 0.83 dL / g, carboxylic acid terminal content: 16 mmol / kg) <Carbodiimide> B-1-1: Carbodiimide compound (Synthesis Example 1 below) B-1-2: Carbodiimide compound (Synthesis Example 2 below) B-1-3: Carbodiimide compound (Synthesis Example 3 below) B-2: Carbodiimide (Stabaxol P-100) manufactured by Lanxess

[0053] Various materials used in the synthesis examples, examples, and comparative examples are listed below. <Diisocyanate compounds> Mixture of 54% by mass of 2,4'-diphenylmethane diisocyanate and 46% by mass of 4,4'-diphenylmethane diisocyanate (mixture of 54% by mass of 2,4'-MDI and 46% by mass of 4,4'-MDI): manufactured by Tosoh Corporation, product name: "Monomeric MDI; Millionate NM" <End-capping agent> Dodecyl alcohol: manufactured by Kanto Chemical Co., Ltd. Cyclohexylamine: manufactured by Tokyo Chemical Industry Co., Ltd. Phenyl isocyanate: manufactured by Tokyo Chemical Industry Co., Ltd. <Carbodiimide catalyst> 3-Methyl-1-phenyl-2-phospholene-1-oxide: Tokyo Chemical Industry Co., Ltd.

[0054] (Synthesis Example 1) 100 parts by mass of a mixture of 54% by mass of 2,4'-diphenylmethane diisocyanate and 46% by mass of 4,4'-diphenylmethane diisocyanate, 21.3 parts by mass of dodecyl alcohol, and 0.5 parts by mass of 3-methyl-1-phenyl-2-phospholene-1-oxide were placed in a reaction vessel equipped with a reflux condenser and a stirrer, and stirred for 2 hours at 100°C under a nitrogen stream. After that, infrared absorption (IR) spectroscopy confirmed that the absorption peak due to the isocyanate group at a wavelength of around 2270 cm-1 had almost disappeared, yielding carbodiimide compound B-1-1 where n=6.

[0055] (Synthesis Example 2) 100 parts by mass of a mixture of 54% by mass of 2,4'-diphenylmethane diisocyanate and 46% by mass of 4,4'-diphenylmethane diisocyanate, 7.9 parts by mass of cyclohexylamine, and 0.5 parts by mass of 3-methyl-1-phenyl-2-phospholene-1-oxide were placed in a reaction vessel equipped with a reflux condenser and a stirrer, and stirred for 2 hours at 100°C under a nitrogen stream. After that, infrared absorption (IR) spectroscopy confirmed that the absorption peak due to the isocyanate group at a wavelength of around 2270 cm-1 had almost disappeared, yielding carbodiimide compound B-1-2 where n=9.

[0056] (Synthesis Example 3) 100 parts by mass of a mixture of 54% by mass of 2,4'-diphenylmethane diisocyanate and 46% by mass of 4,4'-diphenylmethane diisocyanate, 31.7 parts by mass of phenyl isocyanate, and 0.5 parts by mass of 3-methyl-1-phenyl-2-phospholene-1-oxide were placed in a reaction vessel equipped with a reflux condenser and a stirrer, and stirred for 2 hours at 100°C under a nitrogen stream. After that, infrared absorption (IR) spectroscopy confirmed that the absorption peak due to the isocyanate group at a wavelength of around 2270 cm-1 had almost disappeared, yielding carbodiimide compound B-1-3 where n=2. <Masterbatch> C-1-1: Masterbatch made by adding equal amounts of polyethylene (F120N MI: 1.2g / 10min (180℃)) manufactured by Ube Industries and B-1-1. C-1-2: Masterbatch made by adding equal amounts of polyethylene (F120N MI: 1.2g / 10min (180℃)) manufactured by Ube Industries and B-1-2. C-1-3: Masterbatch made by adding equal amounts of polyethylene (F120N MI: 1.2g / 10min (180℃)) manufactured by Ube Industries and B-1-3. C-2-1: Masterbatch made by adding equal amounts of polyethylene (F522N MI: 5g / 10min (180℃)) manufactured by Ube Industries and B-1-1. C-2-2: Masterbatch made by adding equal amounts of polyethylene (F522N MI: 5g / 10min (180℃)) manufactured by Ube Industries and B-1-2. C-2-3: Masterbatch made by adding equal amounts of polyethylene (F522N MI: 5g / 10min (180℃)) manufactured by Ube Industries and B-1-3. C-3-1: Masterbatch made by adding equal amounts of polyethylene manufactured by Ube Industries (J1019 MI: 10g / 10min (180℃)) and B-1-1. C-3-2: Masterbatch made by adding equal amounts of polyethylene manufactured by Ube Industries (J1019 MI: 10g / 10min (180℃)) and B-1-2. C-3-3: Masterbatch made by adding equal amounts of polyethylene manufactured by Ube Industries (J1019 MI: 10g / 10min (180℃)) and B-1-3. C-4-1: Masterbatch made by adding equal amounts of polyethylene manufactured by Ube Industries (J3519 MI: 35g / 10min (180℃)) and B-1-1. C-4-2: Masterbatch made by adding equal amounts of polyethylene manufactured by Ube Industries (J3519 MI: 35g / 10min (180℃)) and B-1-2. C-4-3: Masterbatch made by adding equal amounts of polyethylene manufactured by Ube Industries (J3519 MI: 35g / 10min (180℃)) and B-1-3. C-5-1: A masterbatch made by mixing Sunallomer polypropylene and B-1-1 in a ratio of 6:4. C-5-2: A masterbatch made by adding Sunallomer polypropylene and B-1-2 in a ratio of 6:4. C-5-3: A masterbatch made by adding Sunallomer polypropylene and B-1-3 in a ratio of 6:4. C-6-1: A masterbatch made by adding Sunallomer polypropylene (PM900A MI: 30g / 10min (230℃)) and B-1-1 in a ratio of 6:4. C-6-2: A masterbatch made by adding Sunallomer polypropylene (PM900A MI: 30g / 10min (230℃)) and B-1-2 in a ratio of 6:4. C-6-3: A masterbatch made by adding Sunallomer polypropylene (PM900A MI: 30g / 10min (230℃)) and B-1-3 in a ratio of 6:4. C-7-1: A masterbatch made by mixing Sunallomer polypropylene and B-1-1 in a ratio of 6:4. C-7-2: A masterbatch made by adding Sunallomer polypropylene and B-1-2 in a ratio of 6:4. C-7-3: A masterbatch made by adding Sunallomer polypropylene and B-1-3 in a ratio of 6:4. C-8-1: A masterbatch made by adding equal amounts of Mitsubishi Chemical polybutylene adipate succinate and B-1-1. C-8-2: A masterbatch made by adding equal amounts of Mitsubishi Chemical polybutylene adipate succinate and B-1-2. C-8-3: A masterbatch made by adding equal amounts of Mitsubishi Chemical polybutylene adipate succinate and B-1-3. C-9: Masterbatch made by adding equal amounts of polyethylene (F120N MI: 1.2g / 10min (180℃)) manufactured by Ube Industries and B-2. C-10-1: A masterbatch made by adding equal amounts of A and B-1-1. C-10-2: A masterbatch made by adding equal amounts of A and B-1-2. C-10-3: A masterbatch made by adding equal amounts of A and B-1-3.

[0057] <Masterbatch manufacturing method> Using a twin-screw extruder (manufactured by Japan Steel Works: TEX-30), each polymer other than B-1-1, B-1-2, B-1-3, and B-2 from C-1-1 to C-10-3 above was fed into the extruder, and then the extruder and cylinder temperatures were set as follows when feeding the carbodiimides related to B-1-1, B-1-2, B-1-3, and B-2 into the extruder. The extruder was then kneaded and pelletized to produce each master batch related to C-1-1 to C-10-3. ·C-1-1, C-1-2, C-1-3, C-2-1, C-2-2, C-2-3, C-3-1, C-3-2, C-3-3, C-4-1, C-4-2, C-4-3, C-9: 120℃ ·C-5-1, C-5-2, C-5-3: 160℃ ·C-6-1, C-6-2, C-6-3, C-7-1, C-7-2, C-7-3: 190℃ ·C-8-1, C-8-2, C-8-3: 130℃ ·C-10-1, C-10-2, C-10-3: 260℃

[0058] [Examples 1 to 39, Comparative Examples 1 to 12] Each resin composition was prepared by mixing the raw materials in the proportions shown in Tables 1 to 3, kneading them in a twin-screw extruder (TEX-30, manufactured by Japan Steel Works, Ltd.), and pelletizing them. The temperature of the extruder inlet section when adding the carbodiimide was set to the temperature shown in Table 1, and the temperature of the other extruder cylinder sections was 250°C. Each resin composition was injection molded using an injection molding machine (ROBOSHOT S-2000i100B manufactured by Fanuc Corporation) at a cylinder temperature of 260°C, a mold temperature of 80°C, an injection speed of 150 mm / sec, and a holding pressure of 60 MPa to prepare multipurpose test specimens according to ISO 3167. In Table 1, "(I)" and "(II)" in "Step" indicate that the resin composition was produced by the following steps (I) and (II), respectively, and "-" indicates that the production method does not fall under either (I) or (II). Step (I): A step including a first step of kneading a carbodiimide compound (B) with a resin (C) different from the polyester resin (A) to obtain a masterbatch, and a second step of kneading the polyester resin (A) with the masterbatch. Step (II): A step comprising kneading a polyester resin (A) and a carbodiimide compound (B) in an extruder, wherein the temperature of the extruder inlet section when the carbodiimide compound (B) is introduced into the extruder is 200°C or lower.

[0059] [evaluation] The resin compositions and multipurpose test pieces according to the examples and comparative examples were evaluated as follows. The results are shown in Tables 1 and 2.

[0060] <Isocyanate gas generation rate evaluation>

[0061] 5 mg of each resin composition was heated at 260°C for 10 minutes, and the generated isocyanate gas was measured using a gas chromatograph / mass spectrometer system (GC-MS6890 / 5975 manufactured by Agilent Technologies, Inc.). In Tables 1 and 2, 1 to 3 have the following meanings. 1: The amount of isocyanate gas detected was less than 100 ppm. 2: The amount of isocyanate gas detected was 100 ppm or more and less than 500 ppm. 3: The amount of isocyanate gas detected was 500 ppm or more.

[0062] <Measurement of foreign matter count> The surface of each multipurpose test piece according to the examples and comparative examples was observed with an optical microscope (Canon Inc.: scanner), and the size of the foreign matter (discolored part) was 100 μm. 2 Measure the number of foreign objects above 100cm 2 per 100μm 2 The number of foreign particles having an area equal to or greater than this was calculated.

[0063] [Table 1]

[0064] [Table 2]

[0065] [Table 3]

[0066] As shown in Tables 1 to 3, the resin compositions and molded articles according to the examples containing polyester resin (A) and masterbatches (C-1-1 to C-8-3) had a detected amount of isocyanate gas of less than 100 ppm and a detected amount of isocyanate gas of less than 100 μm 2 The number of foreign objects with an area of 10 or more per 100cm 2 On the other hand, in the resin compositions and molded articles according to the comparative examples containing polyester resin (A) and carbodiimide compound B-2 or masterbatches (C-9, C-10-1 to C-10-3), the detected amount of isocyanate gas was less than 100 ppm or 100 μm 2 The number of foreign objects with an area of 10 or more per 100cm 2In other words, it was found that the resin composition of the present disclosure generated less isocyanate gas and contained less foreign matter, resulting in a better surface appearance. In addition, the resin composition and molded article according to the examples, which are produced by a production method including either of the following steps (I) and (II), have a detected amount of isocyanate gas of less than 100 ppm and a maximum concentration of 100 μm 2 The number of foreign objects with an area of 10 or more per 100cm 2 On the other hand, in the resin composition and molded article according to the comparative example, which were not produced by the production method including either of the following steps (I) and (II), the detected amount of isocyanate gas was less than 100 ppm and 100 μm 2 The number of foreign objects with an area of 10 or more per 100cm 2 In other words, it has been found that a resin composition having a resin composition manufacturing method including either step (I) or (II) generates less isocyanate gas and contains less foreign matter, resulting in a resin composition with a better surface appearance. Step (I): A step including a first step of kneading a carbodiimide compound (B) with a resin (C) different from the polyester resin (A) to obtain a masterbatch, and a second step of kneading the polyester resin (A) with the masterbatch. Step (II): A step comprising kneading a polyester resin (A) and a carbodiimide compound (B) in an extruder, wherein the temperature of the extruder inlet section when the carbodiimide compound (B) is introduced into the extruder is 200°C or lower.

Claims

1. A polyester resin (A), a carbodiimide compound; and a resin composition comprising the The carbodiimide compound contains a carbodiimide compound (B) represented by the following general formula (1), and when the surface of a molded article containing the resin composition is observed with an optical microscope, the surface of the molded article is ２ The number of foreign objects with an area of 10 or more per 100 cm ２ The resin composition, (In general formula (1), R １ , R ３ represents a residue of an organic compound having one functional group capable of reacting with an isocyanate group, excluding the functional group; R １ , R ３ may be the same or different. ２ represents a divalent residue obtained by removing two isocyanate groups from a diisocyanate compound. ２ has a benzene-based aromatic ring directly bonded to the NCN group, and has no or only one substituent at both ortho positions of the benzene-based aromatic ring bonded to the NCN group. １ , X ２ represents a group formed by a reaction between the functional group of the organic compound and the isocyanate group of the diisocyanate compound, and X １ , X ２ may be the same or different, and n represents a number from 1 to 15. The diisocyanate compound contains a mixture of 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, and when the total amount of the diisocyanate compound is taken as 100 mol %, the proportion of the 2,4'-diphenylmethane diisocyanate is 30 to 70 mol %, and the proportion of the 4,4'-diphenylmethane diisocyanate is 30 to 70 mol %.

2. 2. The resin composition according to claim 1, wherein the amount of isocyanate gas generated when the resin composition is heated at 260°C for 10 minutes is less than 100 ppm.

3. The resin composition according to claim 1 or 2, comprising 0.1 to 5 parts by mass of the carbodiimide compound (B) relative to 100 parts by mass of the polyester resin (A).

4. The resin composition according to claim 1 or 2, wherein the polyester resin (A) comprises polybutylene terephthalate.

5. The resin composition according to claim 1 or 2, which contains a resin (C) different from the polyester resin (A).

6. A molded article comprising the resin composition according to claim 1, 100 μm observed on the surface of the molded article through an optical microscope ２ The number of foreign objects with an area of 10 or more per 100 cm ２ less than,

7. 7. The molded article according to claim 6, wherein the amount of isocyanate gas generated when the molded article is heated at 260°C for 10 minutes is less than 100 ppm.

8. The molded article according to claim 6 or 7, comprising 0.1 to 5 parts by mass of the carbodiimide compound (B) relative to 100 parts by mass of the polyester resin (A).

9. A method for producing a resin composition containing a polyester resin (A) and a carbodiimide compound (B) represented by the following general formula (1), the method comprising the following step (I) or step (II): Step (I): A step including: a first step of kneading the carbodiimide compound (B) with a resin (C) different from the polyester resin (A) to obtain a masterbatch; and a second step of kneading the polyester resin (A) with the masterbatch; Step (II): A step comprising kneading the polyester resin (A) and the carbodiimide compound (B) in an extruder, wherein the temperature of the extruder inlet port when the carbodiimide compound (B) is introduced into the extruder is 200° C. or lower; A method for producing a resin composition. (In general formula (1), R １ , R ３ represents a residue of an organic compound having one functional group capable of reacting with an isocyanate group, excluding the functional group; R １ , R ３ may be the same or different. ２ represents a divalent residue obtained by removing two isocyanate groups from a diisocyanate compound. ２ has a benzene-based aromatic ring directly bonded to the NCN group, and has no or only one substituent at both ortho positions of the benzene-based aromatic ring bonded to the NCN group. １ , X ２ represents a group formed by a reaction between the functional group of the organic compound and the isocyanate group of the diisocyanate compound, and X １ , X ２ may be the same or different, and n represents a number from 1 to 15. The diisocyanate compound contains a mixture of 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate, and when the total amount of the diisocyanate compound is taken as 100 mol %, the proportion of the 2,4'-diphenylmethane diisocyanate is 30 to 70 mol %, and the proportion of the 4,4'-diphenylmethane diisocyanate is 30 to 70 mol %.

10. 10. The method for producing a resin composition according to claim 9, wherein the first step in the step (I) is carried out using an extruder, and the temperature of the extruder inlet section when the carbodiimide compound (B) is introduced into the extruder is 200°C or lower.

11. 10. The method for producing a resin composition according to claim 9, wherein in step (II), the carbodiimide compound (B) is introduced into the extruder in the form of a masterbatch containing the carbodiimide compound (B) and a resin (C) different from the polyester resin (A).

12. The method for producing a resin composition according to any one of claims 9 to 11, wherein the masterbatch contains 10 to 90 parts by mass of carbodiimide per 100 parts by mass of the masterbatch.

Images